*

A Panfrost milestone

Tomeu Vizoso avatar

Posted on 07/01/2019 by Tomeu Vizoso

Share this post:

Collabora's latest contibutions to the Panfrost project include support for running Wayland compositors and zero-copy GPU-accelerated clients. Panfrost is a project that delivers a free and open source implementation of a driver for the newest versions of the Mali family of GPUs.

The video

Below you can see glmark2 running as a Wayland client in Weston, on a NanoPC -T4 (so a RK3399 SoC with a Mali T-864 GPU)). It's much smoother than on the video, which is limited to 5FPS by the webcam.

Weston is running with the DRM backend and the GL renderer.

The history behind it

For more than 10 years, at Collabora we have been happily helping our customers to make the most of their hardware by running free software.

One area some of us have specially enjoyed working on has been open drivers for GPUs, which for a long time have been considered the next frontier in the quest to have a full software platform that companies and individuals can understand, improve and fix without having to ask for permission first.

Something that has saddened me a bit has been our reduced ability to help those customers that for one reason or another had chosen a hardware platform with ARM Mali GPUs, as no open driver was available for those.

While our biggest customers were able to get a high level of support from the vendors in order to have the Mali graphics stack well integrated with the rest of their product, the smaller ones had a much harder time in achieving that level of integration, which manifested in reduced performance, increased power consumption and slipped milestones.

That's why we have been following with great interest the several efforts that aimed to come up with an open driver for GPUs in the Mali family, one similar to those already existing for Qualcomm, NVIDIA and Vivante.

At XDC last year we had the chance of meeting the people involved in the latest effort to develop such a driver: Panfrost. And in the months that followed I made some room in my backlog to come up with a plan to give the effort a boost.

At that point, Panfrost was only able to get its bits in the screen by an elaborate hack that involved copying each frame into a X11 SHM buffer, which besides making the setup of the development environment much more cumbersome, invalidated any performance analysis. It also limited testing to demos such as glmark2.

Due to my previous work on Etnaviv I was already familiar with the abstractions in Mesa for setups in which the display of buffers is performed by a device different from the GPU so it was just a matter of seeing how we could get the kernel driver for the Mali GPU to play well with the rest of the stack.

So during the past month or so I have come up with a proper implementation of the winsys abstraction that makes use of ARM's kernel driver. The result is that now developers have a better base on which to work on the rendering side of things.

By properly creating, exporting and importing buffers, we can now run applications on GBM, from demos such as kmscube and glmark2 to compositors such as Weston, but also big applications such as Kodi. We are also supporting zero-copy display of GPU-rendered clients in Weston.

This should make it much easier to work on the rendering side of things, and work on a proper DRM driver in the mainline kernel can proceed in parallel.

Contributing to Panfrost

For those interested in joining to the effort, Alyssa has graciously taken the time to update the instructions to build and test Panfrost. You can join us at #panfrost in Freenode and can start sending merge requests to Gitlab.

Thanks to Collabora for sponsoring this work and to Alyssa Rosenzweig and Lyude Paul for their previous work and for answering my questions.


Visit Tomeu's blog.

Comments (0)


Add a Comment






Allowed tags: <b><i><br>Add a new comment:


Latest Blog Posts

Bootstraping a minimal Arch Linux image

20/03/2019

In this tutorial, we'll look at how to create a functional and simple Arch Linux virtual machine image, that can have network access, display…

An overview of the Panfrost driver

13/03/2019

During the past few months significant progress has been made on the Open Source Arm Mali GPU driver front, culminating in the Panfrost…

Quick hack: Raspberry Pi meets Linux kernel mainline

12/03/2019

With just a few simple steps, you can compile and boot a Raspberry Pi using the Linux kernel mainline source code. Here's how.

News from the Debian Cloud Team

05/03/2019

Since the last Debian release, a number of changes have been made in the Debian Cloud Team, both on the technical & organisational level…

Panfrost update: A new kernel driver

04/03/2019

Following two months of work to develop a new kernel driver for Midgard and Bifrost GPUs, the kernel side of Panfrost is now in a form close…

Modern USB gadget on Linux & how to integrate it with systemd (Part 1)

18/02/2019

A look at how to implement USB gadget devices on Linux machines which have the necessary UDC hardware, automate the manual configfs process…

Open Since 2005 logo

We use cookies on this website to ensure that you get the best experience. By continuing to use this website you are consenting to the use of these cookies. To find out more please follow this link.

Collabora Ltd © 2005-2019. All rights reserved. Website sitemap.